Ok, so, what I understand is that there are a few types of Calc reactors...the kind I'm interested in is the one that uses CO2 to lower ph in a control zone, 'causing the water to eat away at some form of aragonite substrate in the control zone, which then raises the ph before it leaves the control zone and adds Ca? Is this correct? They have a relatively inexpensive CO2 creator at one of the LFSs around here... Would I be able to rig that to a container holding substrate and make sort of a Ca reactor? Or does anyone here know of/have any simple DIY plans to make one? Thanks!

Also - If you have an old refridgerator, that's currently being used to hold a keg (complete with CO2 tank and a tap on the front door of the fridge!!! ) could you make another hole in the side, run some piping through it, back out, then across some heaters (to ensure the water was at a minimum temp) as a chiller? I know it's not really cost effective, but I was wondering. If not, as in the case of the Ca reactor, does anyone have/know of any DIY plans for those? I'm going to be getting my MH setup soon, and I don't want to end up paying $600 for a water cooler! Thanks a lot!

Found a plan that is EXACTLY what I was thinking as far as the fridge cooler goes. But now I'm wondering if I could also use the CO2 tank (I'd get another one) to power my Ca reactor...what do you all think of this plan:

well, I can't speak to the calcium reactor - those plans look sound but still complex - plus, the high pressure CO2 and computer required to regulate it's output are rather expensive

as for a 'party chest' chiller, I've toyed with the idea a few times, but the physics and expense always stops me.

even a regular size fridge has a rather small compressor in it, designed to cool a rather small amount of mass maybe 100-200 lbs of food - they're very undersized for cooling 500+ lbs of water - that is a LOT of mass

granted it doesn't have to keep that 500+ lbs of water under 40 degrees but its still a lot of work.

the other problem is exchanging the heat. saltwater is extremely corrosive, and even freshwater corrodes stainless steel and other metals quickly, which leaves very expensive titanium tubing as the only efficient choice for a heat exchanger, or plastic tubing which is terribly inefficient.

so, how much is titanium tubing? I found a vendor selling 1/4" OD tubing (similar to icemaker line), mininum order 100 feet, at a mere $1.25 a foot ... the pump you'd have to use to force water through 1/4" tubing would add more heat to the water!

I've seen plans for building a proper vapor based heat exchanger out of copper and titanium, but unless you're a real pro at metal working and ac engineering, I think that's unattainable.

the most viable idea I've seen for chilling involves using Mother Earth, its very simple in nature, but hard to do none the less.

basiclly, you dig a big hole as you can as deep as you can (at least 10 feet), and then fill the hole with several 100 feet of 1/2" or 3/4" poly tubing and re-bury it. then, using an air cooled pump, you just circulate tank water through that loop on a continous basis.

the theory is, the temperature of the earth after you get past the 'frost line' stays a constant 68(?) degrees year round - the water flowing through all that tubing slowly looses some of it's heat to the earth and returns cooler.

other than the energy spent on the pump (under 200 watts), you have no expense to run the system

- sorry for the long post - just some of the things I've thought about when thinking about chilling.

I suppose it's an expense I'll have to take. In the future, it's not for now, I was just going ahead and thinking about it. My friend owns a LFS and he usually gets me stuff discounted from his store, so I'll see if he can help me out with this. The cheapest one I found was $260 :|

As far as the chiller goes, hopefully my MH hood won't add a ton of heat to the tank. There'll be 3x250w MH + 4x96w PC for Actinic/03 supplementing. I'm thinking I need to have it about 8" off the water, and the hood comes with fans built into it...if it gets really bad, I can always use the fridge for what it's worth...I'd rather try that, since I use the fridge for drinks anyways... (wrap the tubing around cold aluminum cans...hmmm...) it couldn't hurt. Well, I'll have to look more into that. What's a pump that wouldn't add a lot more heat to the water?

well, if you really want to build a chiller using a fridge, the best way to achieve the end result would be:

the biggest thing you've got working against you in this idea is heat transfer - heat transfer needs one of two things to work - either it needs an efficient heat exchanger or it needs time. since you can't pump 5 gallons of tank water into the fridge, wait 6 hours for it to chill and pump it out again, time is not an option - that leaves a heat exchanger.

for a good heat exchanger you need a thermal mass to absorb and dissipate heat and a good conductor to transfer heat from the water to the thermal mass.

1) thermal mass - there's no better thermal mass than water itself. a 5 gallon or larger container filled as full as possible with water and a few cups of antifreeze will do nicely - add a tiny pump to the bucket like a microjet or similar to keep the water stired up and you're golden

2) good conductor - this is where the tintanium tubing comes into play... but the expense of the tubing is high, although much cheaper than even a low end chiller - anyway, to make up for plastic' inability to conduct heat, you need to give it more contact time with your thermal mass.

3) contact time - contact time with the thermal mass and surface area of contact are the two biggest things to worry about. just buying 200-300 feet of plastic tubing and coiling it into your bucket won't accomplish much because the tubing will be insulating itself from the water since most of the tubing won't even be touching the water, it'll just be touching other parts of the tubing - the solution for this is some sort of grid, to keep it spaced.

4) spacing grid - cost of the grid is minimal, assembly time might take a few hours. basiclly what I envision is 6 panels of acrylic, all the same shape and size, drilled identically full of holes (best done with a drill press, just clamp all pieces together and drill away), spaced evenly apart left to right, top to bottom. then you weave the tubing around and around and around through these grids, starting with the inside holes working outward and upward at the same time. - be sure to space out the panels evenly so they support the tubing. - what you end up with would be a very large coil of tubing, spaced neatly apart, ready to exchange heat with the thermal mass

submerging the heat exchanger into the thermal mass you're ready to 'charge up' the thermal mass - set the fridge as cold as it will go and turn on the little pump - don't circulate any water through the tubing yet - give the fridge 4-6 hours to get that water bucket nice and cold first - you did add some antifreeze right - a bucket full of ice won't help any and might damage the heat exchanger.

once the bucket of water is very cold, it's time to turn on the main pump and start pushing some water - time how long it takes from when you switch on the pump to when you see water returned, this is the amount of contact time your water has in the chiller ... the more time the better - if its coming out right away, you didn't use nearly enough tubing - stick a thermometer under the output and see if it's actually any colder

there ya go - cost of the project should be less than $200 (excluding the pump) and should only take a day to do.

well, I can't speak to the calcium reactor - those plans look sound but still complex - plus, the high pressure CO2 and computer required to regulate it's output are rather expensive

as for a 'party chest' chiller, I've toyed with the idea a few times, but the physics and expense always stops me.

even a regular size fridge has a rather small compressor in it, designed to cool a rather small amount of mass maybe 100-200 lbs of food - they're very undersized for cooling 500+ lbs of water - that is a LOT of mass

granted it doesn't have to keep that 500+ lbs of water under 40 degrees but its still a lot of work.

the other problem is exchanging the heat. saltwater is extremely corrosive, and even freshwater corrodes stainless steel and other metals quickly, which leaves very expensive titanium tubing as the only efficient choice for a heat exchanger, or plastic tubing which is terribly inefficient.

so, how much is titanium tubing? I found a vendor selling 1/4" OD tubing (similar to icemaker line), mininum order 100 feet, at a mere $1.25 a foot ... the pump you'd have to use to force water through 1/4" tubing would add more heat to the water!

I've seen plans for building a proper vapor based heat exchanger out of copper and titanium, but unless you're a real pro at metal working and ac engineering, I think that's unattainable.

the most viable idea I've seen for chilling involves using Mother Earth, its very simple in nature, but hard to do none the less.

basiclly, you dig a big hole as you can as deep as you can (at least 10 feet), and then fill the hole with several 100 feet of 1/2" or 3/4" poly tubing and re-bury it. then, using an air cooled pump, you just circulate tank water through that loop on a continous basis.

the theory is, the temperature of the earth after you get past the 'frost line' stays a constant 68(?) degrees year round - the water flowing through all that tubing slowly looses some of it's heat to the earth and returns cooler.

other than the energy spent on the pump (under 200 watts), you have no expense to run the system

- sorry for the long post - just some of the things I've thought about when thinking about chilling.

Geo-Thermal Heating/Cooling.

They use it on homes, as well. The temputure at a set depth stays constant. Seems rather overkillish for just one fishtank, however.